Automatic telephone system



c v 1 I Aug 927 R. F. GOULD AUTOMATIC TELEPHONE SYSTEM Filed AuZ- 28. 1925 -Imran DIP--- E05 E Enulcl Patented Aug. 30, 1927.

1,640,568 UNITED STATES PATENT" OFFICE.

ROY F. GOULD, OF CHICAGO, I LLINOES, ASSIGNOR, BY MESNE ASSIGNMENTS, TO AUTO MATIC ELECTRIC INC, OF CHICAGO, ELLINOIS, A CORPORATION OF DELAWARE AUTOMATIC TELEPHONE SYSTEM.

Application filed August 28, 1925. Serial No. 53,030. f

This invention relates in general to antomatic telephone systems, in which connections are established through the medium of subscriber controlled automatic switches,

but is more particularly concerned with au-' ton'iatic systems including party lines, and the object 01" the invention is to providea new and improved method of and apparatus for selectively signaling the party line stations. The arrangement herein described is simple and inexpensive and on that account is especially well adapted for use in small systems, such as private automatic exchanges, although its use is not necessarily so limited.

The means by which the foregoing object is accomplished will be fully set forth hereinatter, reference being had to the accompanying drawing, in which is shown sufficient of the apparatusin a small automatic telephone system to enable the invention to be explained and understood.

The reference character A indicates an automatic substation of the grounded bell type, which has the usual talking instrumentalities and the calling device S for control-v ling the central otiice switches.

Substation A is connected with the cen tral exchange by. line conductors 11 and 12 which terminate in the individual line or trunk selecting switch (1. The line switch G is a switch or the well known rotary type whose wipers have no normal position and move in a forward direction only. As is well known, the function of the individual line switch is to extend its associated line to an idle selector switch or connector switch when the receiver is raised at the substation to initiate a call.

One of the connector switches, to which the line switch Chas access in the instant case,

in common withother similar line switches,

operating or not operating shaft spring 97,-

positioned so as to close its contact on some level above the first level, as for instance the third, and the switch always releases after the first digit. The second and third digits are used to operate the connector the usual manner to complete the connection to the called line. I I

One of the lines to which the connector'E has access is shown at the upper right hand corner-of the drawing and comprises line conductors 111 and 112. This line is a twoparty line, and substations A and A? are connected in bridge or the line with their bells grounded in the well known manner. The line switch is associated with the party line at theexchange, and is similar to the line switch C.

Having described the equipment and the apparatus in general, 'a more detailed description of the various operations will now, be given. For this purpose, itwill be as sumed that the subscriber at substation A desires to establish a connection with a subscriber at substation A ,;wh0se telephone number is 234. I

When the receiver is removed at the calling station, a circuit is"comp1eted over the lineconductors 11 and 12 for the slowactg ing line relay 14. Upon energizing, relay 14 closes a circuit at its armature-17, which includes the. winding of the-switching relay 15 and the stepping magnet 16 in series; and at its armatures 18 connects the test wiper 26 to the above circuit ata point midway between'the said switching relay and the magnet. The operation now depends upon whether the'trunk line with which the lineswitch wipers are associated is busy or is not busy. If the trunk line is busy, there will be a ground potential upon the said contact with which the test wiper 26 is in engagement, the switching relay 15 will be short circuited, and the stepping magnet 16, which interrupts its own circuit, will be operated 9 in the manner of a buzzer to advance the switch wipers in search of an idle trunk line. We may assume, in the present case,- that when the call is initiated the wipers are advanced to the idle trunk terminating in bank contacts 2880, inclusive. When the wipers arrive at this set of contacts the short circuit is removed from the switching relay 15 and the operation of the stepping magnet 16 will cease because of the high resistance of the said switching relay. The latter relay, however, is energized and grounds the test wiper 26 at its armature 20, and at itsarmatures 19 and 21 disconnects the line conductors 11 and 12 from ground and from the winding of the line re lay 14;, respectively, and extends them by way of Wipers 25 and 27, and bank contacts 28 and 30 to the line relay 50 of the connector E.' When'the line is extended as above described, the line relay 50 is energized over the line circuit to close a circuit for the slow to release relay 51. Upon energizing, relay 51 prepares a circuit for the vertical magnet 59 at its armature 68, and at its armature 67 connects ground to'the release trunk conductor 49, thereby completing a holding circuit for the line switch C in the well known manner.

The calling subscriber may now operate his calling device in accordance with the first digit in the desired number. Tn response to the interruptions in the line circuit thus produced, the line relay 50 is deenergized twice, and at thefirst deenergization transmits a current impulse to the vertical magnet 59 overthe following circuit: Grounded armatures 66 and its resting contact, working contact and armature 68, resting contact and ofi-normal spring 64, winding of the slow to release series relay 53, and the winding of the vertical magnet 59 to battery. By the operation of thevertical magnet, the wipers 9193, inclusive, are raised step by .step until they stand opposite the dialled level, which in the present instance is below the level where the shaft of the switch operates the spring 97, as previously pointed out. The slow to release series relay 53 is energized in series with the vertical magnet and by means of its armature 73 maintains the circuit of the vertical magnet intact after the regular ofi-normal springs have been shifted, which occurs on the first vertical step. At the end of the vertical movement of the switch, relay 53 is deenergized and closes a circuit for release magnet 61 at armature 7 2 which may be traced from grounded armature 69 and its resting contact, resting contact and armature 72, ofi normal spring 63 and its working contact, and release magnet 61 to battery. Release magnet 61, upon energizing, releases the shaft carrying the wipers 91-93, inclusive, allowing the same to restore to normal and open the off normal springs in the well known nanner. As a further result of the energization ofthe release magnet 61, a circuit is closed at armature 65 for relay 52 which may be traced from grounded armature 67 and its working contact, armature 65 and its working contact, lower winding of relay 52, armature 71 and its resting contact, and release magnet 61 to battery. Relay 52 does not, however, energize over this circuit until the shunt at the armature 62 is removed by the opening of the off normal springs. YVhen the shunt is removed relay 52 energizes and locks up to ground armature 67, by way of its armature 70, which armature is adjusted to make before armature 71 breaks. At armature 69,'relay 52 removes ground from the contact of armature 72 and the shaft spring 97 (the latter operation being effective to prevent relay 58' from energizing on the second digit regardless of the value of such digit); and at armature 71 opens the circuit of release magnet 61.

Release magnet 61, upon deenergizing, opens the initial energizing circuit of relay 52 at armature .65.

The calling subscriber ma now operate his calling device in accordance with the second digit in the desired number, the digit 3. In response to the interruptions int-he line circuit thus produced, the vertical magnet of the connector is again operated under control of the line relay to raise the wipers 9193, inclusive, to the particular level in which is terminated the line including substation A in the manner already described above. At the end of the vertical movement of the switch, relay 53 deenergizes and transfers the operating circuit from the vertical magnet 59 to the, rotary magnet 60. The previously traced operating circuit for the release magnet 61 is open at armature 69, and although shaft spring 97 is now actuated relay 58 does not energize.

The subscriber will now operate his calling device in accordance with the next and last digitof the desired number, the digit 4:. When the calling device is operated, the

line relay 50 responds as before and sends impulses to the rotary magnet 60 over the following circuit: Grounded armature 66 and its resting contact, workingcontact and armature 68, normally open contacts controlled by the off-normal spring'64, armature 73 and its resting contact, stepping relay 5 1-, resting contact and armature 78, resting contact and armature 82, and rotary magnet 60 to battery. By the operation of the rotary magnet, the wipers 91-93, inclusive, are rotated step by step and are finally brought to rest in engagement with the bank contacts on which the line including substation A is terminated. These bank contacts are indicated in the drawing by the reference characters 94, 95 and 96.

The slow to release relay 5%: is energized in series with the rotary magnet and retains its armature attracted throughout the rotary movement of the switch. At its armature 7 5, relay 54': connects test wiper 92 with the t st relay 56, and at its arn'iature 7a the said relay 5 L closes a shunt around the contact at armature S2 of the test relay. The latter operation is to prevent the test relay from opening the rotary magnet circuit while the test wiper is passing over busy test con tacts.

It will be assumed first that the called line is busy. Such being the case, when the tp s t wiper 92 arrives at test contact 95, it

from heating up through its low upper winding to ground direct. When the slow to release relay deenergizes at the end of the rotary movement of the switch, the test relay 56 establishes a locking circuit for itself at its armature 83 which may be traced from ground on the release trunk conductor d9, armature 83 and its working contact, normally closed contacts controlled by armature 75, resistance 76, resting contact and armature 85, and upper winding or the test relay 56 to battery. Relay 56 also opens the rotary magnet circuit at its-armature 82, thus rendering the impulse circuit ineitective at this time in case the calling subscriber dials another digit in error. Relay 56 also, at its armature 84, connects a lead from the busy signaling machine, labeled Busy, to the lower talking conductor. By

this latter operation, an audible signal is transmitted to the calling subscriber, and, being advised thereby that the called line is inaccessible for the time being, he will hang up his receiver.

Having explained the operation which takes place when the called line is busy, it will now be assumed thatthe line is idle when called. Under these circumstances,

when the test wiper 92 arrives at'the test i contact 95, it will find no ground potential and the test relay 56 will not be energized. Then when the slow to release relay 54 deenergizes at the end of the rotary movement f the switch, a circuit is completed for the switching relay 55 as follows: From the grounded release trunk conductor 49, armature 83 and its resting cont-act, lower winding of switching relay 55, resting contact and armature 7 5, test wiper 92, bank contact 95, winding of the switching relay 116, and the winding of the stepping magnet 114 to bat tery. Relays 55 and 116 are energized in se ries over the above circuit, and the latter relay is operated to clear the called line of its normal battery and ground connections in the line switch (1 It should be noted that the relay 116 is not. fully operated at this time, due to a mechanical interlocking arrangement between the armature of this relay and the armature of slow acting line relay 115, and the wipers of the line switch C are not connected up. In the connector E, when the switching relay 55 is energized, it establishes a locking circuit for itself at its armature 79, grounds the test wiper at ar mature 77, opens the impulsing circuit of magnet and prepares a circuit for slow acting ring cut-off relay 57 at armature 78,

and closes at armature 81 the signaling circuit which may be traced from grounded generator GEN, through the contacts of the ringing interrupter, resting contactand armature 87, armature 81 and its workingeontact, resting contact and armature 90,-hne

wiper 93, bank contact 96,-line-conductor 111, and through the condenserandbell by way of the switchhook at the called substation A to ground. The above circuit is intermittently opened-and closed by the operation of the ringing interrupter and the ringer at substation A is thus operated at intervals to signal the called subscriber. As a further result of the energization of switching relay 55, a circuit is closed at armature which provides for transmitting atone signal to the calling subscriber during the ringing opera tion. hen the called subscriber at substation A removes his receiver to answer thecall, the ringer thercat is disconnected and the ringing circuit is completed over a metallic circuit including the other line conductors 112 and the upper winding of the ring cut-oft relay 57 at the connector E, which may be traced as follows: Grounded generator GEN, through the contacts of the ringing interrupter, resting contact and ar mature 87, armature 81 and its working contact, resting contact and armature 90, line wiper 93, bank contact 96, line conductor 111, through the receiver, transmitter and calling device of the substation A to the line'conductor 112, bank contact 9 1, line wipers 91, armature 88 and its resting contact, top winding of the ring cut-off relay 57 working contact and armature 78, resting contact and armature 82, and rotary magnet 60 to grounded battery. The rotary magnet will not energize over this circuit but the ring cut-off relay 57 energizes and establishes a locking circuit for itself at armature 86 to the grounded release trunk con-- duo-tor 49, opens the ringing circuit at armature 87 and at the latter armature and armature finally completes the talking circuit.

The required connection has now been es tablished and the calling and called subscribers may converse as desired. Current for the transmitter at substationA is sup.-

plied through the windings of relay 50, and

current for the transmitter at substation A is supplied through the windings of the test or busy relay 56, now used as a back bridge relay, which circuit may be traced from grounded release trunk conductor 49, arma return to line conductor 112, bank contact" but the latter is of no consequence at this time as the busy circuit is now open at the normally closed contacts controlled by an mature 87 When the conversation is finished, both subscribers will hang up their receivers.

When the receiver is replaced at substation A, the line and release relays 50 and 51 are deenergizcd and the latter relay disconnects ground from the release trunk conductor 45), thereby causing relays 55, and 57 to deenergize, and line switch C to restore to normal. Relay 52, upon deenergizing, closes a circuit for release magnet 61 at armature 69, which circuit has already been traced, and which. operates to restore the connector E to normal position in the usual manner.

A. brief explanation will, now be given of the manner in which the other station on the line is signalled. Substation A may be assigned the telephone number 334-, the first digit 3 corresponding to the level at which the shaft spring 97 is actuated. The operations are exactly the same as when substation A is called, except that when the shai't spring 97 is operated on dialling the first digit a circuit is closed for wiper reversing relay 58, which may be traced from grounded armature 69 and its resting contact, shatt spring 97 and its working contact, normally closed contacts controlled by armature 89, and wiper reversing relay 58 to battery Relay upon energizing, closes a locking circuit for itself. at its armature 89 to the release trunk, and at its armatures 88 and 90 switches the wipers so that the signaling current is now sent over line conductor 112, instead of 111, to ring the bell at suhsta' tion A In the foregoing, a specific system has been assumed in which those subscribers whose ringers are connected like the ringer at station A, that is, to the positive side of the line, have telephone numbers beginning with the digit 2; while those subscribers whose ringers are connected to the other sides of their respective lines have telephone numbers beginning with the digit 3. It will be understood, however, that some variation from this is possible because the reversing relay 58 energizes it the digit 3 or any larger digit is called as the first digit, and will not energize if the first digit is less than 3; consequently, subscribers in the first men tioned class may have telephone numbers beginning with either 2 or 1, while subscrib ers in the second class may have telephone numbers beginning with any digit from 3 to O, inclusive.

vate exchange located all in one building, for

example, the first digit may be used as a floor designation, as well as to accomplish the station selection, while it the stations are scattered in various buildings, the first digit in the number of any station may correspond to the building in which such station is located. In the case of party lines, of course, the two stations on any line must be located on different floors, or in different buildings, in order for this scheme to be followed.

Having described my. invention, what I consider to be new and desire to have protected by Letters Patentwill be pointed out in the appended claims.

hat is claimed is: r

1. In a' telephone system, an automatic switch for extending a connection to a line, atter being first operated and released, said switch including a pair of line wipers, a source ot .gnaling current, said source being normally associated with one of said, wipers, and means responsive to a preliminary operation ot said wipers corresponding to a particular digit for transferring said source into association with the other wiper.

2. In a telephone system, a two-party line having -substation ringers connected from opposite sides of said line to ground, an automatic switch for extending a connection to said line, means for preliminarily operating and eleasing said switch, a source of signaling current, and means in said switch for applying said source to one side or the other or" said line depending upon the extent of said preliminary operation,

3. In a telephone system, a party line connector switch responsive to a plurality of digits in a called number, two-party lines and levels of selectable terminals therefor in d switch, a source of signaling current, and electromagnetic means for operating d switch, said means responsive to the first one of said digits for raising said switch to a desiredle'vel and releasing same and responsive thereafter to. one or more digits tor selecting the terminals of one of said party lines and tor applying said source to one or the other side of the line depending upon whether said switch was raised to a predetermined level or not responsive to the first digit.

4. In a telephone system, a connector switch including a pair of line wipers and responsive to a plurality of digits in a called number, electro-magnetic means responsive to the first digit for stepping said switch to any desired level and releasing same, a source of signaling current normally associated with one wiper, and a wiper reversing sponsive to the first digit for stepping said switch to any desired level and releasing same, said first digit thereby controlling means for ringing over one side or the other of said lines as well as serving as a location identification. I

'7. In a telephone system, an automatic switch for extending a connection to a line, said switch including a pair of line wipers, a source of signalling current, said source being normally associated with one of said wipers, means for repeatedly operating the switch to determine which party on the desired line is to be signalled and to select the line, means for releasing the switch responsive to its first operation, and means movements, a wiper reversing relay, means for energizing said relay responsive to a predetermined primary movement, and means for restoring the switch upon completion of said primary movement.

9. In a telephone system, a connector switch having line wipers, means for moving said wipers in three successive moveinentsjto establish a connection, means effective upon the completion of the first movement for causing the restoration of the wipers, signalling means, and means depended upon the extent of the first movement for connectin said signalling means to one or the other of said wipers.

10. In a telephone system, a connector having line wipers and talking conductors, a reversing switch for connecting said conductors to said wipers, means for operating said wipers in accordance with certain successive digits in a desired number, means for releasing said connector after it has been operated in accordance with the first of said digits and before it has been operated in accordance with the remaining digits, and means effective it the first of said digits is greater than a certain amount to cause the operation of the reversing switch.

11. In an automatic telephone system, the method of establishing connections to a desired party on a party line which consists in operating a connector in accordance with one digit in the desired number, in conditioning the connector to signal the line over one or the other of the talking conductors depending upon the extent to which the connector is operated, and in then first releasing the connector and then reoperating it to select the desired line. I

In witness whereof, I hereunto subscribe my name this 25th day of August,'A. 'D.

ROY F. GOULD. 

